. >> hi, jim, wendy. similar to a traditional mammogram but it actually images the breast tissue in 3d. that helps doctors diagnose cancer earlier and hopefully save lives. >> he said i would be really shocked if this was not cancer. >> reporter: a cancer diagnose sis almost always surprising. when doctors recently diagnosed 58-year-old patty taylor with breast cancer, it was especially stunning because it had never shown up on her mammogram. >> which to me was astounding. just absolutely astounding. >> reporter: that's because the tumor was only 7 milliliters long which makes it difficult to pick up on a conventional mammogram. but the alexandria woman had a new type of screening. a 33 mammogram. the doctors say gives them a closer look at the breast tissue. >> the procedure is performed by having a series of very low dose images. reconstructed so that the breast tissue can be seen in as many as 60, 70, even 80 then sections or thin slices. >> reporter: conventional mammograms are two dimensional. it tak